Heart pulse detector with speed control for treadmill

ABSTRACT

The present invention offers a heart pulse detector. Two pairs of contact electrodes mounted on each handrail of treadmill separately. A electrocardiography heart pulse detector built in the control panel of the treadmill has input terminal which electrically connected to the contact electrodes. A front end circuit within the heart pulse detector receives the electrical cardio signals of a user from the input terminal and preprocesses the electrical cardio signals for later processing by the reminder functional blocks of the heart pulse detector. A hand touching detection circuit assembly in the heart pulse detector is also connected to the input terminal. The hand touching detection circuit sense the signals from the input terminal and send out hand on/off data for using to control the speed of the treadmill and to control the operation of the heart pulse detection.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heart pulse detector, and more particularly to a heart pulse detector which detects a user's heart pulse signal as well as the touching action style of the user's hands via the same contact electrodes and outputs heart pulse data and hand touch signals for controlling the speed of a treadmill accordingly.

2. Description of the Related Art

For electrical treadmill with electrocardiography heart pulse monitor needs contact electrodes which are usually mounted on the handrails of treadmill to derive the electrical cardio signals from the user when the hands of the user grasp or touch on the electrodes. In some cases, there may be circuits in the heart pulse monitor to sense the presence of the user's hands contacting with the electrodes and then to control the operation of functions of heart pulse monitor itself only.

For conventional electrical treadmill, there should have an extra apparatus to provide a user input means for user to input the commands to control the speed of the treadmill when the user is running or walking on it. There are varieties of user input apparatus for using to control the speed of a treadmill. For example, keypad or key switches are commonly user input apparatus for speed control of a treadmill. The technology is used in U.S. Pat. No. 6,830,541, to Wu, the system uses this technology consists of at least a movable switch mounted on an arm of the main flame and includes a holder secured on the arm. Some other examples are using different kind of sensors such as contact switch to sense the touching of user and control the speed of a treadmill. For example, the U.S. Pat. No. 6,761,688, to Chang, the system use one contact switch mounted on a corresponding one of the arms of the treadmill to cause an analog signal to control the speed. Some other sensors are using photoelectric device to sense the motion of hands of a user or the position of a user and generate commands to control the speed of treadmill. For example, the U.S. Pat. No. 6,135,924, to Gibbs, et al, the system use an optical sensor monitors the position of a user on the treadmill and automatically varies the speed of the treadmill. Some other sensors are using ultrasonic device to sense the motion of hands of user or the position of user and generate commands to control the speed of a treadmill. For example, the U.S. Pat. No. 6,719,668, to Huang, the system use two ultrasonic transmitter receiver units respectively installed in the upright support of the house flame at two sides. Another example is the U.S. Pat. No. 5,368,532, to Farnet, the system use sensors located below an upper run of the belt for sensing the position of a user, and a controller for controlling the speed of the belt in accordance with the position of the user relative to the sensors, causing the belt to accelerate, decelerate.

All extra apparatus mentioned above for speed control of treadmill increase the complexity of manufacture and then increase the cost of treadmill.

OBJECTS OF THE INVENTION

It is therefore an object of the invention to provide a heart pulse detector which detects a user's heart pulse signal as well as the touching action style of the user's hands via the same contact electrodes and outputs heart pulse data and hand touch signals for controlling the speed of a treadmill accordingly, thus simplify the manufacture of treadmill and save the cost of treadmill.

DISCLOSURE OF THE INVENTION

A first aspect of the present invention teaches a heart pulse detector used in a treadmill that including a base frame, a motor driven tread belt, a rightup frame with a left handrail and a right handrail, a control panel, the heart pulse detector including: A plurality of sensor on the left handrail and the right handrail for obtaining electro cardio signal from the user; An instrument amplifier for amplifying the electro cardio signal; A common circuit for providing a common reference voltage to the instrument amplifier; A heart pulse detector for detecting a heart pulse signal in response to the amplified electro cardio signal from the output of the instrument amplifier and for producing a digital pulse that is synchrony with the heart pulse signal and is transmitted to the microprocessor in the control panel for calculating the heart pulse rate of the user; A plurality of sensor comprising a first pair of contact electrodes and a second pair of contact electrodes; The first pair of contact electrodes comprising a first contact electrode and a second electrode mounted on the left handrail of the treadmill separately; The second pair of contact electrodes comprising a third contact electrode and a fourth electrode mounted on the right handrail of the treadmill separately; The first contact electrode and the third contact electrode being connected to the inputs of the instrument amplifier; The second contact electrode and the fourth electrode being connected to the output of the common circuit; A hand touch detection circuit for receiving the signals from the first contact electrode and the third contact electrode and for producing a plurality of hand touch signal to indicate whether the first pair of contact electrodes and/or the second pair of contact electrodes are touching with the hand of the user; A plurality of hand touch signal will be transmitted to the microprocessor in the control panel for performing the speed control of the treadmill; The common circuit will output a high level voltage when a plurality of hand touch signal indicate that the first pair of contact electrodes and second pair of contact electrodes are not touching with the hand of the user.

Another preferred embodiment of the present invention teaches a hand touch detection circuit consist a data encoder for converting a plurality of hand touch signal into a formatted serial data signal for transmitting to the microprocessor in the control panel for performing the speed control of the treadmill.

The hand touch detection circuit further consists: A first inverter for responding to the signal at the first contact electrode and providing a first left input signal; A first comparator for responding to the signal at the first contact electrode and providing a second left input signal; A second inverter for responding to the signal at the third contact electrode and providing a first right input signal; A second comparator for responding to the signal at the third contact electrode and providing a second right input signal; A circuit for providing reference voltage to the positive input of the first comparator and the positive input of the second comparator; A processor for responding to the first left input signal, the second left input signal, the first right input signal, the second right input signal and providing a first hand touch signal to indicate whether only the first pair of contact electrodes are touching with the hand of the user and providing a second first hand touch signal to indicate whether only the second pair of contact electrodes are touching with the hand of the user and providing a third hand touch signal to indicate whether the first pair of contact electrodes and second pair of contact electrodes are touching with both hands of the user at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the invention will be more fully understood with reference to the description of the best embodiment and the drawing wherein:

FIG. 1 is a perspective view of a treadmill constructed according to the present invention.

FIG. 2 is a block diagram of the present invention.

FIG. 3 is a block diagram of hand touch detector of the present invention.

FIG. 4 is a block diagram of hand touch processor of hand touch detector of the present invention.

FIG. 5 is a block diagram of common driver of the present invention.

FIG. 6 is a flow chart illustrating the operation of hand touch processor of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The foregoing and other advantages of the invention will be more fully understood with reference to the description of the best embodiment and the drawing as the following description.

The preferred embodiment of present invention is illustrated in FIGS. 1-6.

As shown in FIG. 1, a treadmill 1 comprises a bass frame 2 having a tread belt 3 which is driven by a motor mounted in the bass frame 2. A pair of upright frame members 4 on the head side of the base frame 2 support a control panel 5 at an upper portion of the upright frame members 4, a left handrail 6 and a right handrail 7 are mounted on a respective side thereby. A pair of contact electrodes 11, 12 are mounted on the left handrail 6 by a holder 8. Another pair of contact electrodes 13, 14 are mounted on the right handrail 7 by a holder 9.

Referring to FIG. 2, a heart pulse detector circuitry 10 includes a hand touch detector 31, a common driver 32, an instrument amplifier 33, a band-pass filter 34, a low-pass filter 35, a peak detector 36, and a one-shot circuit block 37.

The contact electrode 11 and the contact electrode 14 are electrically connected together to terminal 21 which is connected to the output of the common driver 32 and also is connected to the common input of the instrument amplifier 33. The contact electrode 12 is electrically connected to terminal 22 which is connected to one of the inputs of the instrument amplifier 33 and also is connected to one of the inputs of the hand touch detector 31. The contact electrode 13 is electrically connected to a terminal 23 which is connected to other input of the instrument amplifier 33 and is also connected to the other input of the hand touch detector 31.

The detail circuits of the hand touch detector 31 are shown in FIG. 3. The input of the hand touch detector 31 which connected to terminal 22 is connected to an input of inverter 66 and to a negative input of a comparator 68 and to one of the terminals of a resistor 64. The other input of the hand touch detector 31 which connected to terminal 23 is connected to the input of an inverter 67 and to the negative input of a comparator 69 and to one of the terminals of a resistor 65. The other terminal of both resistor 64 and resistor 65 are both connected to the ground. In order to keep high impedance at terminal 22 and terminal 23, the prefer value of the resistor 64 and the resistor 65 is 10M ohm each. The positive inputs of the comparator 68 and the comparator 69 are both connected to a reference voltage terminal 71 which is derived from the resistor 62 and the resistor 63. The output of the inverter 66 is connected to terminal 72 and is named as “L-INPUT A”. The output of the inverter 67 is connected to terminal 73 and is named as “R-INPUT A”. The output of the comparator 68 is connected to terminal 74 and is named as “L-INPUT B”. The output of the comparator 69 is connected to terminal 75 and is named as “R-INPUT B”. Terminals 72, 73, 74, 75 are connected to the inputs of a hand touch processor 81. One of the outputs of the hand touch processor 81 which connected to terminal 24 is used to control the operation of the heart pulse detection. The other output of the hand touch processor 81 which connected to terminal 25 is used to send out the data of events of hand touch for speed control of the treadmill.

As shown in FIG. 4, the hand touch processor 81 includes an events detector 91, a timer 92, and an events encoder 93. The events detector 91 analyze the input signals from terminals 72, 73, 74, 75 and combine with the control of the operation of the timer 92, then sent out the signals of events of hand touch through terminals 94, 95, 96 to the inputs of the events encoder 93. Terminal 94 is the event signal of “BOTH HAND”. Terminal 95 is the event signal of “LEFT HAND”. Terminal 96 is the event signal of “RIGHT HAND”. The detail operation of the events detector 91 is shown in FIG. 6 by a logic flow chart. One output of events encoder 93 come from buffer of terminal 94 and is connected to terminal 24. The other output is encoded serial data of events of hand touch and is connected to terminal 25. The prefer embodiment of events encoder 93 is a three bits Manchester code encoder. There are six event data and named as “LEFT HAND ON”, “LEFT HAND OFF”, “RIGHT HAND ON”, “RIGHT HAND OFF”, “BOTH HAND ON”, and “BOTH HAND OFF”. Referring to FIG. 2, as the microprocessor 52 receives the data of events of hand touch from terminal 25, then speed controller 53 or incline controller 54 will receives command sent by microprocessor 52 and the speed or incline of the treadmill is adjusted.

As shown in FIG. 5, the common driver 32 is built by an operational amplifier 45. The positive input of operational amplifier 45 is connected to a reference voltage terminal 49 which is derived from a resistor 42 and a resistor 43. The output and the negative input of the operational amplifier 45 are connected together and are connected to a switch 46 and terminal 21. The signal of terminal 24 controls the operation of the common driver 32. When the state of terminal 24 is at logic low, switch 41 and the operational amplifier 45 are turn off and switch 46 is turn on, then a high level voltage is output to terminal 21. When the state of terminal 24 is at logic high, switch 41 and operational amplifier 45 are turn on and switch 46 is turn off, then a level of half supply voltage (i.e. ½ VCC) is output to terminal 21.

At the start of the heart pulse detector circuitry 10 after power on or function is enable, all the state of terminals 94, 95, 96 are set to off (logic low). So the state of terminal 24 is at logic low and the common driver 32 outputs a high level voltage to terminal 21.

When all the contact electrodes 11, 12, 13, 14 are not touched by user's hand, then the signals at terminals 22, 23 are both at low voltage level. The states of terminal 72, 73 are both at logic high, thus there is no state changed at terminals 94, 95, 96.

When the contact electrodes 11, 12 are touched by a user's hand, then a high level voltage is conducted to terminal 22 from terminal 21 through contact electrodes 11, 12 and the user's hand. The state of terminal 72 is then changed to logic low and timer 92 is started by events detector 91. As the user's hand keep in touch with contact electrodes 11, 12 for period larger than a timing T2 (for example, 100 msec), then the state of terminal 95 is set to logic high and a “LEFT HAND ON” signal is sent out to terminal 25. When the user's hand moves out the contact electrodes 11, 12, then signal on terminal 22 goes down to low voltage and the state of terminal 72 comes back to logic high. Timer 92 will be started again by events detector 91. After a timing T3 (for example, 100 msec) has been passed, the state of terminal 95 is set to logic low and a “LEFT HAND OFF” signal is sent out to terminal 25.

When the contact electrodes 13, 14 are touched by the user's hand, then a high level voltage is conducted to terminal 23 from terminal 21 through contact electrodes 13, 14 and the user's hand. The state of terminal 73 is then changed to logic low and the timer 92 is started by the events detector 91. As the user's hand keep in touch with the contact electrodes 13, 14 for a period larger than a timing T2 (for example, 100 msec), then the state of terminal 96 is set to logic high and a “RIGHT HAND ON” signal is sent out to terminal 25. When the other user's hand touch on the contact electrodes 11, 12 following, the state of terminal 72 now is changed to logic low, then the events detector 91 set the timer 92 start. As this state continue for a timing T1 (for example, 200 msec), the state of terminal 96 is set to logic low and a “RIGHT HAND OFF” signal is sent out to terminal 25. Following, then both the state of terminals 94, 24 are set to logic high and a “BOTH HAND ON” signal is sent out to terminal 25.

Referring to FIG. 3, as there is logic high state at terminal 24, the switch 61 and the comparators 68, 69 are turn on. The voltage at terminal 71 will be far below half of the supply voltage by let the value of resistor 63 far larger than the value of the resistor 62. So both the state of terminals 74, 75 is held at logic low when the voltages at terminals 22, 23 are conducted to the level of half supply voltage. Then the states of terminals 94, 24 are kept unchanged.

Referring to FIG. 2, as the state of terminal 24 is at logic “high”, all the functional blocks in the heart pulse detector 10 are turn on. The electrical cardio signals derived from the user's hands through the contact electrodes 11, 12, 13, 14 are conducted to the inputs of the instrument amplifier 33 via terminals 21, 22, 23. The output of the instrument amplifier 33 is connected to the input of the band-pass filter 34 which extracts the so call “R” wave signal from the electrical cardio signals. The output of band-pass filter 34 is connected to the input of the low-pass filter 35 which will filter out the noise whose frequency is higher than the “R” wave signal. The filtered “R” wave signal then come into the peak detector 36 and the peak signal of the “R” wave signal is picked out thereby. When the peak signal of the “R” wave signal is sent into the one-shot circuit 37, a one-shot heart pulse signal is output to terminal 26 and input to the microprocessor 52. After receives a sequence of one-shot heart pulse signals from terminal 26, the microprocessor 52 will perform the processing and counting to calculate out the real heart pulse rate of the user and shows the result at display 55.

When the user release one hand or both hands from the contact electrodes 11, 12 or/and the contact electrodes 13, 14 for a period longer than timing T4 (for example, 200 msec.), both the state of terminals 94, 24 are set to logic high and a “BOTH HAND OFF” signal is sent out to terminal 25. Then the function of heart pulse detection is turn off and the microprocessor 52 will stop the calculation of heart pulse rate of the user. As one of the user's hand continuing touches on the contact electrodes 11, 12 or the contact electrodes 13, 14, the state of terminal 95 or terminal 96 is not changed and no more data of events of hand touch will be sent out to terminal 25. Only when both of the user's hands are moved out from the contact electrodes 11, 12, 13, 14, the events detector 91 will go back to its initial state.

The heart pulse detector of the present invention can be used as a user input apparatus to control the speed of treadmill. It is also can be used as a user input device to change the operation mode of treadmill or to control incline angle of treadmill.

Although specific embodiments of the invention have been disclosed, it will be understood by those having skill in the art that minor changes can be made to the form and details of the specific embodiments disclosed herein, without departing from the scope of the invention. The embodiments presented above are for purposes of example only and are not to be taken to limit the scope of the appended claims. 

1. A heart pulse detector used in a treadmill that including a base frame, a motor driven tread belt, a rightup frame with a left handrail and a right handrail, a control panel, the heart pulse detector comprising: a plurality of sensor on the left handrail and the right handrail for obtaining electro cardio signal from the user; an instrument amplifier for amplifying the electrocardio signal; a common driver for providing a common reference voltage to said instrument amplifier; a heart pulse detector for detecting a heart pulse signal in response to the amplified electro cardio signal from the output of said instrument amplifier and for producing a digital pulse that is synchrony with the heart pulse signal and is transmitted to the microprocessor in the control panel for calculating the heart pulse rate of the user; said plurality of sensor comprising a first pair of contact electrodes and a second pair of contact electrodes; said first pair of contact electrodes comprising a first contact electrode and a second electrode mounted on the left handrail of the treadmill separately; said second pair of contact electrodes comprising a third contact electrode and a fourth electrode mounted on the right handrail of the treadmill separately; said first contact electrode and said third contact electrode being connected to the inputs of said instrument amplifier; said second contact electrode and said fourth electrode being connected to the output of said common driver; a hand touch detection circuit for receiving the signals from said first contact electrode and said third contact electrode and for producing a plurality of hand touch signals to indicate whether said first pair of contact electrodes and/or said second pair of contact electrodes are touching with the hand of the user; said plurality of hand touch signal will be transmitted to the microprocessor in the control panel for performing the speed control of the treadmill; said common driver will output a high level voltage when said plurality of hand touch signal indicate that said first pair of contact electrodes and/or said second pair of contact electrodes are not touching with the hand of the user.
 2. The heart pulse detector as recited in claim 1, wherein said hand touch detection circuit further comprises a data encoder for converting said plurality of hand touch signal into a formatted serial data signal for transmitting to the microprocessor in the control panel for performing the speed control of the treadmill.
 3. The heart pulse detector as recited in claim 2, wherein said hand touch detection circuit further comprises: a first inverter for responding to the signal at said first contact electrode and providing a first left input signal; a first comparator for responding to the signal at said first contact electrode and providing a second left input signal; a second inverter for responding to the signal at said third contact electrode and providing a first right input signal; a second comparator for responding to the signal at said third contact electrode and providing a second right input signal; a circuit for providing reference voltage to the positive input of said first comparator and the positive input of said second comparator; a processor for responding to said first left input signal, said second left input signal, said first right input signal, and said second right input signal, and providing a first hand touch signal to indicate whether only said first pair of contact electrodes are touching with hand of the user and providing a second first hand touch signal to indicate whether only said second pair of contact electrodes are touching with hand of the user and providing a third hand touch signal to indicate whether said first pair of contact electrodes and second pair of contact electrodes are touching with hands of the user at the same time.
 4. The heart pulse detector as recited in claim 3, wherein said processor further comprises a timer for generating a predetermined period of timing signal as a reference for processor itself. 